21.31.3 The INFORMATION_SCHEMA TP_THREAD_GROUP_STATS Table

This table reports statistics per thread group. There is one row
per group. The table has these columns:

TP_GROUP_ID

The thread group ID. This is a unique key within the table.

CONNECTIONS_STARTED

The number of connections started.

CONNECTIONS_CLOSED

The number of connections closed.

QUERIES_EXECUTED

The number of statements executed. This number is incremented
when a statement starts executing, not when it finishes.

QUERIES_QUEUED

The number of statements received that were queued for
execution. This does not count statements that the thread
group was able to begin executing immediately without queuing,
which can happen under the conditions described in
Section 8.11.6.2, “Thread Pool Operation”.

THREADS_STARTED

The number of threads started.

PRIO_KICKUPS

The number of statements that have been moved from
low-priority queue to high-priority queue based on the value
of the
thread_pool_prio_kickup_timer
system variable. If this number increases quickly, consider
increasing the value of that variable. A quickly increasing
counter means that the priority system is not keeping
transactions from starting too early. For
InnoDB, this most likely means
deteriorating performance due to too many concurrent
transactions..

STALLED_QUERIES_EXECUTED

The number of statements that have become defined as stalled
due to executing for a time longer than the value of the
thread_pool_stall_limit
system variable.

BECOME_CONSUMER_THREAD

The number of times thread have been assigned the consumer
thread role.

BECOME_RESERVE_THREAD

The number of times threads have been assigned the reserve
thread role.

BECOME_WAITING_THREAD

The number of times threads have been assigned the waiter
thread role. When statements are queued, this happens very
often, even in normal operation, so rapid increases in this
value are normal in the case of a highly loaded system where
statements are queued up.

WAKE_THREAD_STALL_CHECKER

The number of times the stall check thread decided to wake or
create a thread to possibly handle some statements or take
care of the waiter thread role.

SLEEP_WAITS

The number of THD_WAIT_SLEEP waits. These
occur when threads go to sleep; for example, by calling the
SLEEP() function.

DISK_IO_WAITS

The number of THD_WAIT_DISKIO waits. These
occur when threads perform disk I/O that is likely to not hit
the file system cache. Such waits occur when the buffer pool
reads and writes data to disk, not for normal reads from and
writes to files.

ROW_LOCK_WAITS

The number of THD_WAIT_ROW_LOCK waits for
release of a row lock by another transaction.

GLOBAL_LOCK_WAITS

The number of THD_WAIT_GLOBAL_LOCK waits
for a global lock to be released.

META_DATA_LOCK_WAITS

The number of THD_WAIT_META_DATA_LOCK waits
for a metadata lock to be released.

TABLE_LOCK_WAITS

The number of THD_WAIT_TABLE_LOCK waits for
a table to be unlocked that the statement needs to access.

USER_LOCK_WAITS

The number of THD_WAIT_USER_LOCK waits for
a special lock constructed by the user thread.

BINLOG_WAITS

The number of THD_WAIT_BINLOG_WAITS waits
for the binary log to become free.

GROUP_COMMIT_WAITS

The number of THD_WAIT_GROUP_COMMIT waits.
These occur when a group commit must wait for the other
parties to complete their part of a transaction.